DE2719287A1 - IMPLANTABLE LEAD WITH REINFORCING MANDRIN - Google Patents

Description

PATENT Attorney DIPL.-INC. GERHARD SCHWAN

ELFENSTRASSE 32 · D-8000 MUNICH »3

Ger. P-257

MEDTRONIC, INC. 3055 Old Highway Eight, Minneapolis, Minn. 55440 / V. St. A,

Implantable lead with stiffening stylet

709846/0972

TELEPHONE: 089/601103 »· CABLE: ELECTRICPATENT MUNICH

The invention relates to an implantable lead carrying an electrode for connecting a living organ to the body an electrical device, and in particular the combination of such a lead with an improved stiffening stylet. The one provided with such a stiffening stylet implantable lead can be used for various purposes. In the following it is based on an endocardial pacemaker and measuring line for connecting a pacemaker pulse generator to heart tissue explained in more detail. Endocardial Pacemaker and sensing leads, such as those known from US Pat. No. 3,348,548, have one or more hollow, coiled wire conductors, which are sheathed with an appropriate insulating material, for example silicone rubber that is substantially inert to body media and tissues. You are also with one at the rear End of each conductor attached, hollow terminal pin and an electrically conductive electrode provided, which at the front End of the conductor sits and can be brought into contact with the endocardium of a patient. A cavity extends through each pin and its associated coiled wire conductor up to the electrode at the leading end of the lead; she takes a stiffening stylet out of a cylindrical, stainless steel Steel wire that stiffens the conduit to allow it to advance through the patient's venous system and into the tip the right ventricle to ease. Will the stylet come out

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pulled out of the line, the line is very flexible; it is difficult to advance the line in this state. Further details regarding the structure and the application such endocardial pacemaker leads are for example known from US Pat. No. 3,348,548 and therefore do not need to be explained here.

The conventional endocardial pacemaker lead is on its anterior end has an electrode with a relatively blunt tip, which is inserted into the trabecula at the tip of the right ventricle can be stored. A likewise known, improved endocardial pacemaker lead (US Pat. No. 3,974,834) is equipped with a rigid, electrically conductive helix at the front end of the cable, which has a sharp point and is in the endocardium can be screwed in. The improved line can be stored in body tissue and there permanently set or, if necessary, remove them again, without the need for complicated or space-consuming electrode feed devices Sleeves or catheter introducers are required to open the veins and the tricuspid valve in front of the sharp tip to protect the helix. The attachment of this improved implantable Conduction takes place in that a bypass made of a flexible, non-conductive material is provided, the extends away from the silicone rubber sheath of the cable over the length of the helix and closes on contact with tissue.

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Can be pushed back when the helical electrode is in the tissue is screwed in. One or more traditional mandrins Stainless steel wire are used to make the improved implantable lead during insertion and positioning to stiffen.

The invention is based on the object of creating an implantable lead that is even safer to handle.

The implantable lead according to the invention is with one or several mandrins are provided, which make a positioning of conventional endocardial leads (e.g. US-PS 3,348,548) or leads with helical electrodes (e.g. US-PS 3,974,834). According to the invention, the stylet has at least one Mandrel wire suitable for stiffening the electrical conductor on, the length of which is such that it stretches the conductor beyond its length in the relaxed state thus increasing the stiffness of the conduit and its ability to transmit torque from the rear to the front end. With one end of the stylet wire is also one Coupling device connected which can be brought into engagement with the connection element of the conductor and can be retained in engagement.

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According to a preferred embodiment, the carries intravascular line at its posterior end one or several pins that can be connected to a pulse generator while the lead at the front end is connected to a or several electrodes are provided, which through endotheliales Tissue can be safely stored through a body organ or can be permanently connected to it. Of the Stiffening stylet can be inserted into a cavity, the one in the lead from the pin along the conductor up to the electrode is enough. The part that can be inserted into the cavity of the stylet wire has a length slightly greater than that corresponding length of the cavity. At the rear end of the stylet is a coupling device, for example in the form a button or screw is provided which engages the pin or other terminal element of the conductor can be brought in order to stretch the line in this way and to increase its rigidity and torque transmission capacity increase. The stylet preferably runs through the connecting element the conductor through. The stylet increasing the torsional rigidity of the cable by stretching the cable preferably carries a button with a hole at the rear end, which the connecting element, for example a connecting pin, the lead and can come into frictional engagement therewith, the stylet wire around a predetermined length is pushed into the conductor cavity, whereby the line

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is stressed (tensioned) and thereby the torsional and Axial rigidity of the line can be increased. Through the coupling between the bore of the button or the like and the connecting element (e.g. connecting pin) the mandrin and the entire line can be rotated by turning the knob.

In the case of a bipolar implantable lead with two connecting pins, Conductor and electrodes are combined, two stiffening mandrels can expediently be provided; the Coupling devices, e.g. buttons, of the stiffening mandrel can expediently wear connecting links in order to connect the two coupling devices to one another. With such a mutual connection, the stylets act as a unitary arrangement that increases the rigidity and torsional strength of the line and allows the direct transmission of torque to the front end of the line, which through Rotating the interconnected coupling devices applied will.

The electrode arranged on the line preferably has a rigid, corkscrew-like coil made of an appropriate, conductive electrode material; this helix can be screwed into endothelial tissue by removing the line and the stiffening sleeve (s)

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be rotated inside. The one or more heads of the line are preferably constructed from coiled wire, which is inside one or more .Hohlraum in a flexible sheath and which is stretched within the flexible sheath when the stylet wire is fully advanced.

The invention is described below on the basis of a preferred exemplary embodiment explained in more detail. In the accompanying drawings show:

1 shows a preferred embodiment of the implantable, intravascular Line according to the invention in a partially cut-away representation, also in the cavities of the Line partially inserted stiffening mandrel to recognize are,

FIG. 2 shows the line according to FIG. 1 after embedding and permanent fixation in the one forming the tip of the right ventricle of the heart Tissue,

3 shows, partially in longitudinal section, a detailed representation of the button and part of the wire of the stiffening mandrel as

4a and 4b are end views of two buttons according to FIG. 3, the are connectable to each other.

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The intravascular endocardial lead shown in FIG has an elongated lead portion 10, a front electrode portion 12 and a rear terminal end portion 13 on. In the illustrated bipolar The embodiment is the line with two tightly wound, coiled ones Conductors 14, 15 are provided, each of which is in the form of a spring coil, which is wound around and along the conductor axis is. The resilient coiled conductors 14, 15 extend into separate cavities of a sleeve or jacket 16 made of electrically insulating material over the full length of the Line 10. The conductors 14, 15 can be independent of one another and stretched and bent by the jacket 16.

Each of the coiled conductors 14, 15 consists of an electrical conductive material that has a low electrical resistance and is resistant to corrosion by body media is. A platinum-iridium alloy, for example, is suitable for this purpose. The jacket 16 is made of an electrical one insulating material, preferably a silicone rubber, made. This can be, for example, the marketed by Dow Corning Corporation under the name "Silastic". This The material is also inert and is well tolerated by body tissue.

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At the rear end 13 of the line 10 are the conductors 14 and 15 introduced into tubular connecting pins 17 and 18 and with this connected by squeezing. A fork-shaped shoe 19 made of the same material as the jacket 16 is around the connecting pins 17, 18, the terminal ends of the coiled conductors 14, 15 and the jacket 16 are molded around, the pins 17 and 18 protrude beyond the shoe 19. Leave the connector pins insert yourself into the sockets of the pulse generator. The pulse generator can be any, appropriate, act implantable pulse generator, for example a generator known from US Pat. No. 3,057,356 Art.

At the front end of the line 10 are two electrodes 22 and 23 welded to the ends of the conductors 14 and 15 or on other way electrically connected. The electrode 23 is preferably in the form of a ring made of a corrosion-resistant, electrically conductive material, for example platinum or a platinum alloy, a metal oxide or a carbon compound. Ring electrode 23 includes both coiled conductors 14 and 15. Electrode 22 is similar Way electrically connected to the front end of the coiled conductor 14. The one running between electrodes 22 and 23 Piece of the coiled conductor 14 is insulated by means of a jacket 24 made of the same material as the jacket 16

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liert, which is sprayed around the conductor 14. To this
Way, with the exception of electrodes 22 and 23, the entire
Line isolated from the body when connected to the pulse generator.

The line 10 described so far according to FIGS. 1 and 2
corresponds to the line known from US Pat. No. 3,348,548. It
it turned out that such a line is the permanent one
rapidly repeating bending stresses over years
can withstand. The conductor turns are proportionate
tightly wound, although a small gap may be provided between adjacent turns. By enggewik- ¹ kelten structure is provided for a maximum number of conductor turns per unit length; the stresses are optimally distributed. The formation of the ladder in the form of coiled springs also allows considerable stretching within
the elastic limits of the material as well as a distribution of the bending stresses in the longitudinal direction of the conductor, the
otherwise focus on a certain point. Both the conductors 14 and 15 and the insulating ones
Sheath 16, 19 and 24 are elastic. In conjunction with the coiled structure of the ladder, this ensures maximum distribution of the bending forces.

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In the lead of FIG. 1, the electrode 22 has tissue by abutting parts and parts fixing the electrode. Furthermore, an insertion sleeve is firmly connected to the line, Cuff or jacket to protect the intravascular Body vessels are provided against damage by the part penetrating the tissue during the insertion of the line. This covering pulls away from the one piercing the fabric and the section used for fixation automatically returns when it enters and / or through endothelial tissue be pushed through. The electrically conductive electrode 22 has the shape of a corkscrew with a circular cross section or a helix 25 with approximately five turns. The helix has a length of approximately 6.4 mm and a nominal outside diameter, which is approximately equal to that of the insulated body of the lead 10 and is approximately 3.2 mm. the Helix 25 can, with the exception of its tip, or one or more Turns or parts of turns with the help of a thin layer be insulated from a non-conductive material, which increases the stimulation current density in relation to the conductive electrode surface can be. The helix 25 is welded to a connection part 27 of the conductor 14 or electrically in some other way conductively connected. Preferably, the helix 25 is with a sharpened tip 26 for piercing endocardial Fabric and provided with a sufficient number of turns so that when the line 10 and the electrical

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de 22, by rotating the rear end section 13, the coil 25 passes through the endocardial tissue into myocardiales Tissue advanced and there through the turns of the helix 25 can be held and prevented from relocating.

An introducer cuff or sheath 28 fits over the coils and the tip 26 of the coil 25; she is with the that Connection part 27 surrounding jacket 24 tightly connected. The casing 28 consists of a silicone rubber or a other appropriate material; it has the shape of a thin-walled, concertina-like folded tube, the number of folds at least equal to the number of turns of the helical electrode 25 is. In the relaxed state illustrated in FIG. 1, the folds stretch; they form angles with each other of about 90 °. In the relaxed state, the casing has a length of approximately 7.6 mm, an outer maximum pleat diameter of approximately 4.0 mm and a wall thickness of approximately 0.25 mm.

The cuff or jacket 28 is designed so that it protects the body vessel or vein through which the line to the endothelial tissue of a body organ is inserted until the desired implantation site is reached. If used in conjunction with a Pacemaker the lead is located in the heart chamber and

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ready to be attached to the desired location of the endocardium to become, push the accordion-like folds of the casing 28 together; they fold over that Turns of the coil 25 back while it is screwed into the endocardium.

Fig. 2 shows a completely inserted lead, its electrode 22 is permanently fixed in the tissue forming the tip of the right ventricle.

As can be seen from Fig. 2, the heart 30 shown in section has four chambers, namely the right ventricle 31, the right atrium 32, left atrium 33, and left ventricle 34. An endocardial lead is preferred Introduced through a vein on the low pressure side of the heart. The right or left external jugular vein or the right or left cephalic vein 35, the superior vena cava 36, the right atrium 32, tricuspid valve 37 and right ventricle 31 can be used. While inserting the line 10 this must take a curved path through the veins and pass through the valve 37 without damaging the tissue will. It is also desirable that the conduit 10 be small in cross-section in order to be easily pushed through the veins and not to cause excessive stretching of the veins.

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In the position shown, the line 10 ′ is screwed into the endocardium at the tip of the right ventricle 31. The "spiral 25" is screwed in by turning the whole Line by manipulating the rear end 13 of the line 10 accordingly. If the line 10 'during the When twisting is pressed against the endocardium, the folds subside the cuff or cover 28 'continues to come closer together; the turns of the coil 25 slip at the open end of the Casing 28 'and twist into the heart tissue.

Clinical trials with the described line 10 showed that the coil 25 is easily and repeatedly inserted through the vein and the heart valve, screwed into the endocardium, unscrewed again and pulled out of the body in the same way without the tissue, with which the line comes into contact is injured to a significant extent. When the line is unscrewed, the folds of the cover 28 'stretch; the dressing slides back over the turns of the helix 25.

In FIGS. 1 and 2, stylets 20 and 21 are shown. Everyone Mandrin 20, 21 has a mandrel wire 40, 41 in the form a cylindrical stainless steel wire of a predetermined length and a button 50 and 51, respectively. The buttons 50, 51 are

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at the rear ends of the wires 40, 41 in connection with Fig. 3 explained manner attached. The stylet wires 40, 41 extend through central cavities in the pins 17, 18, and the conductors 14, 15 through to end points which are within the connection part 27 and the ring electrode 23 lie. In the illustrated embodiment the stylet wires 40, 41 extend through the exposed ones Cavities in the conductors 14, 15 in section 42 of FIG. The cavity of the conductor 14 is sufficient in the embodiment shown up to the folded-over end of the helix 25 within the connecting part 27 at the front end section 12.

In Fig. 1, the stylet 20 and the stylet 21 are in one Position shown in which they emerge from the cavities of the conduit 10 are partially pulled out; in the illustration according to FIG. 2, the stylet 20 and the stylet 21 extend fully into the concerned cavities into it. The length of the mandrel wires 40, 41 extending from the end faces 52, 53 of the buttons 50, 51, are chosen so that they correspond to the length of the cavities concerned in the ladders 14, 15 correspond. The stylet wire 40 is therefore longer than the wire 41, reducing the distance between the End points of the relevant cavities on the electrodes 22 and 23 is taken into account.

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In FIG. 2, the mandrels 20, 21 extend fully into the cavities shown. The buttons 50, 51 are partially pushed onto the pins 17, 18 and are in engagement with them. When the buttons are coupled to pins 17, 18 in this way, an additional piece of stylet wire is required 40, 41 pushed into the cavity in the order of magnitude of 5 mm, whereby the line 10 is stretched. By the stretching exerts tension on the coiled conductors 14, 15 and the jacket 16; these will be proportionate rigid; her fortune, one applied to the rear end Transferring torque to the front end is increased.

Fig. 3 shows, partly in section, an elevation of the button 50 (exemplary embodiment) and part of it attached thereto Mandrel wire 40, which extends into the pin 17. Of the Knob 50 is provided with an axial bore 54 through which the wire 40 axially passes and into which the pin 17 (as in FIG Fig. 2 illustrates) is pressed into it. The button 50 is for example made of a non-conductive plastic; he holds the rear end 55 of the in the manner indicated Wire 40, which extends through the bore 54.

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The bore 54 tapers gradually; the downsizing of the bore diameter provides a friction fit with the pin 17, stretching the conduit 10. The extent the extension of the line 10 can be determined by the surgeon, since one or both buttons 50, 51 are on the relevant Pin 17, 18 pressed and the pins 17, 18 whole or only can be partially pressed into the bore 54.

On the outer surface of the buttons 50, 51 is a row of Ribs 56 are formed which allow the surgeon to grasp the buttons 50, 51 securely during implantation. Corresponding 4a and 4b, the ribs 56 are evenly distributed around the circumference of the buttons 50, 51.

FIGS. 4a and 4b show end views of the buttons 50, 51 and show fastening parts 57, 58. The fasteners 57, 58 are approximately the same length as the ribs 56 and replace on each of the buttons 50, 51, respectively one of the ribs 56. The protruding attachment part 57 can snap into female fastener 58, causing buttons 50, 51 to act as one unit Component are connected. As can be seen from Fig. 2, when the buttons 50, 51 are connected to each other and on the pins 17, 18 are pressed, the whole rear end of the line is rotated by the interconnected-

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knobs 50, 51 are rotated. Due to the longitudinal dimension of the fasteners 57, 58 can be one of the buttons 50, 51 further pressed onto the associated pin 17, 18 than the other. The fastening parts 57, 58 remain with one another engaged.

As for the attachment of the line 10 to the heart 30 according to FIG As far as is concerned, the buttons 50, 51 in their operative position impart tension and rigidity to the line 10 as well Torque transmission capabilities that allow the surgeon to easily screw the electrode 22 into the endocardium. The line 10 is prevented from twisting and wind up on itself when the rear end is rotated. Rather, the desired rotational movement is transferred from the rear end to the front electrode 25 so that it is easily screwed into the endocardium or can be screwed out of this.

While the illustrated and described preferred embodiment of the line is two-pole, it goes without saying that the principle explained can also be used without further ado with single-pole lines, ie lines which have only one electrode and one conductor. The electrodes can have a different shape or can be located at a different point on the line. While the line 10 in connection with a

ner pacemaker assembly has been described understands it is further that the line 10 is also used for other stimulation tasks can be used.

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Claims (15)

1./Implantable lead from a facing body media and tissue substantially inert material, with an electrically insulated, flexible conductor of predetermined length, a connecting element arranged at the rear end of the conductor, one at the front end of the conductor, in contact with body tissue bringable electrode, a cavity running in the longitudinal direction of the insulated conductor and a stiffening stylet, characterized in that the mandrin can be inserted into the cavity at least one for stiffening the electrical conductor Mandrel wire, the length of which is greater than the length of the cavity and has a coupling device connected to one end of the mandrel wire, which coupling device is connected to the connecting element can be brought into engagement when the mandrel wire is inserted into the cavity, in order to maintain the engagement with the conductor in order to increase the torque transmission from the rear to the front end of the line. 2. Line according to claim 1, characterized in that the coupling device a button with a hole for receiving the connecting element and for producing frictional engagement with the Has connecting element. 7ua84fi / O972 ORIEiNAL INSPECTED 27 1 9787 3. Line according to claim 2, characterized in that the Mandrel wire extends into the bore in the axial direction and as a connecting element a pin for receiving the mandrel wire is provided. 4. Line according to claim 3, characterized in that the Bore has a predetermined length and a tapered diameter and that the outside diameter of the pin is greater than at least a portion of the tapered diameter of the bore. 5. Implantable line made of a material that is essentially inert to body media and tissue, with two electrical lines insulated, flexible conductors of predetermined length, a first and a second at the rear ends the conductor arranged connection element, a first and a second located at the front ends of the conductor, with body tissue can be brought into contact electrode, a first and a second in the longitudinal direction of the insulated Conductor running cavity and a stiffening mandrin, characterized in that the stylet at least a mandrel wire which can be introduced into the first cavity for stiffening the electrical conductor and whose length is greater than is the length of the first cavity, and a coupling device connected to one end of the mandrel wire. 709846 / Ü972 2719787 has that with the connecting element when inserting the stylet wire is engageable in the cavity to, while maintaining the engagement, the conductor for the purpose of increasing the To stretch torque transmission from the rear to the front end of the line. 6. Line according to claim 5, characterized in that the coupling device a button with a bore for receiving the connecting element and for producing a frictional engagement with having the connection element. 7. Line according to claim 6, characterized in that the mandrel wire extends in the axial direction into the bore and the connecting element has a pin for receiving the mandrel wire, which can be introduced into the bore. 8. Line according to claim 7, characterized in that the bore has a predetermined length and a tapered diameter and that the outside diameter of the pin is greater than at least a portion of the tapered diameter of the bore is . 709846/0972 9. Line according to claim 5, characterized by a second Stiffening stylet with at least one additional stylet wire, which can be introduced into the second cavity to stiffen the electrical conductor, and one with the rear cavity Further connected to the end of the further mandrel wire Coupling device with a connecting device for mutually connecting the two arrangements as well for coupling the two connection elements and the two mandrel wires is provided. 10. Line according to claim 9, characterized in that the coupling device of the two mandrels has a first and a has second button, and that the connecting device with a seated on the first button protruding Coupling member and a female coupling member arranged on the second button is provided. 11. Line according to claim 9, characterized in that at least one of the electrodes has a helix with a sharp tip that can be screwed into body tissue. 12. Implantable line made of a material that is essentially inert to body media and tissue, with an electrical one insulated, flexible conductor of predetermined length, one arranged at the front end of the conductor, with 709846 / Q972 - <- 2719787 s: Body tissue that can be brought into contact with an electrode and a cavity running in the longitudinal direction of the insulated conductor, characterized by at least one insertable into the cavity for stiffening the electrical conductor Mandrel wire, the length of which is greater than the length of the cavity is, as well as by a coupling device connected to the mandrel wire and engageable with the line, by means of which at least part of the protruding length of the mandrel wire in order to increase the acting on the line Stress can be pressed into the cavity. 13. Implantable lead from an opposite body media and Fabric essentially inert material, with two electrically insulated, flexible conductors of predetermined length, a first and a second connection element seated at the rear ends of the conductors, a first and a second, located at the front ends of the ladder, electrode which can be brought into contact with body tissue, a first and a second cavity which extend in the longitudinal direction of the insulated conductors run, and a first and a second stiffening mandrin, characterized in that each stylet one in one of the cavities for the purpose of stiffening of the relevant electrical conductor insertable mandrel wire, as well as one coupled to the mandrel wire Has connecting device, by means of which the two mandrels can be coupled to one another at the rear end of the line 709846/0972 are . 14. Line according to claim 13, characterized in that the two stylets with a first and a second button are provided, and that the connecting device is a projecting coupling member seated on the first button and a female coupling member disposed on the second button. 15. Line according to claim 13 or 14, characterized in that that the electrodes are provided with a helix with a sharp tip that can be screwed into body tissue. 709846 / Ü972